The present invention relates to a liquid level control system for swimming pools or the like and, more particularly, to a liquid level control system for use with a liquid or pool reservoir having an inlet, a main drain or outlet usually at the bottom of the pool, and having outlets located at a predetermined liquid maintenance level in the reservoir such as the surface of the water in the pool.
For many applications requiring the use of a liquid reservoir, it is desirable to maintain the reservoir at or near a predetermined liquid maintenance level. This is not so much of a problem where significant fluctuations in the level of the liquid in the reservoir are desirable or at least can be tolerated without adverse impact upon the intended use. It will be appreciated, of course, that one example of this type of reservoir is a household water system which may utilize the pressure within a storage tank to signal a pump and/or valves to control the liquid level. The sensed or controlling level in the storage tank itself may not be of such significance as long as the water pressure and an adequate supply of water throughout the house is maintained. This can be a severe problem, however, where significant fluctuations in the level of the liquid cannot be tolerated or at least are undesirable due to the potential adverse impact upon the intended use. Where the liquid reservoir should be maintained at or near a predetermined liquid maintenance level, it is desirable to be able to automatically refill the reservoir to the predetermined level to immediately replace even small quantities of liquid lost due to evaporation or any other cause. Such a problem is critical in maintaining proper levels in swimming pools or the like. For instance, a skimmer may be employed with a swimming pool for skimming water from the pool reservoir at the surface of the pool and circulating the skimmed water through a filtration system and returning filtered water back to the pool. The cost, size and operation of the skimmer is dependent upon the water level of the pool being maintained at all times at or near a predetermined level. It is essential to have a uniform "cut" of pool water over the weir of the skimmer. This is because the bacteria count is highest at the water surface. Thus, much cleaner water will be obtained if the circulating water through the filter is taken from the outlet at the water level at the surface of the water than at the main drain outlet. In addition, if the water level falls below the skimmer weir and sufficient air is drawn into the circulation system, the pump will lose its prime and frequently the seals will become destroyed because of heat. There are other reasons for maintaining the water level substantially constant at all times during use.
This invention is directed to a liquid level control system for use with a swimming pool or like liquid reservoir for purposes described above. Means are positioned relative to the surface of the water in the pool reservoir for sensing an interface between liquid and gas, or water and air with the interface sensing means producing a signal when the interface falls below a predetermined level. Means responsive to the signal produced by the interface sensing means are provided with the signal responsive means moving to an operative position when the signal is produced by the interface sensing means. Means associated with the signal responsive means are provided for supplying water from an external supply to the pool reservoir permitting water to flow into the pool reservoir when the signal responsive means is moved to the operative position. With these features of construction, the liquid level control system is well suited for maintaining a pool reservoir at a predetermined liquid maintenance level.
Additional details of the liquid level control system include the interface sensing means being a fluid amplifier and the signal produced by the fluid amplifier being a fluid pressure signal. It is also contemplated that the signal responsive means will be a fluid valve and the operative position of the fluid valve will, of course, be an open position. Further, the water is carried by the pipe or conduit from the external water supply to the pool reservoir.
Considering the invention in greater detail, the liquid level control system is well adapted for use with a pool reservoir having an inlet and an outlet as well as means including a water surface skimmer at the outlet for circulating water between the outlet and the inlet. Means associated with the fluid amplifier also is provided for communication of the fluid amplifier with the water circulation means. The system further includes means associated with the fluid valve for communication of the fluid valve with the external water supply so as to permit water to flow into the pool reservoir only when a signal is developed by the fluid amplifier.
Still further details of the present invention include the water circulation means being a circulation conduit for carrying the water from the outlet to the inlet. The water circulation means also includes a pump operatively associated with the circulation conduit for circulating the water from the outlet to the inlet. It is further contemplated that the communication means joining the fluid amplifier and the water circulation means will be a tube leading from the circulation conduit to the fluid amplifier. The tube is preferably joined to the circulation conduit through the tube at a position upstream of the inlet and downstream of the pump. Additionally, the fluid amplifier continuously receives a portion of the water from the circulation conduit through the tube to develop the fluid pressure signal whenever the pool reservoir drops below the predetermined maintenance level.
Other details include the liquid communication means being a supply conduit leading from the external water supply to the pool reservoir. The fluid valve is then advantageously disposed within the supply conduit at a position intermediate the external water supply and the pool reservoir. With these features of construction, the fluid valve can control the flow of water from the external water supply into the pool reservoir thereby controlling and maintaining the pool reservoir at the predetermined maintenance level.
In an alternative embodiment, the liquid level control system is still adapted for use with a pool reservoir having an inlet and having an outlet located at the predetermined water maintenance level of the pool. It includes means at the inlet for restricting flow of the water including a restrictive orifice through which the liquid passes from the circulation conduit into the pool reservoir. A first tube also is provided through which the fluid amplifier communicates with the water in the circulation conduit adjacent the flow restriction means and a second tube is provided, as well through which the fluid pressure signal is transmitted from the fluid amplifier to the fluid valve. It further includes water supply means for adding water to the pool reservoir from an external water supply including a supply conduit with the fluid valve being disposed within the supply conduit.
Still additional details of the alternative embodiment include the fluid amplifier continuously receiving a portion of the water in the circulation conduit through the first tube to develop a fluid pressure signal. The flow restriction means preferably includes a cap associated with the circulation conduit at the inlet with the restrictive orifice in the cap causing an increased pressure in the water in the circulation conduit adjacent the inlet. The cap includes first and second taps extending therethrough with the first tube communicating with the water in the circulation conduit through the first tap and the second tube transmitting the fluid pressure signal to the fluid valve through the second tap. The first tap advantageously is larger than the second tap, with the first tube extending from the fluid amplifier into the first tap and the second tube extending from the fluid amplifier to the fluid valve passing through the second tap and the circulation conduit. Additionally, the fluid valve may suitably be a diaphragm valve having first and second chambers with one of the chambers communicating with the fluid amplifier through the second tube and the other of the chambers communicating with atmospheric pressure.
A significant advantage of the present invention is that it may be provided in kit form for addition to already installed swimming pools. The liquid level control kit will include a fluid amplifier, a fluid valve, a cap, a first tube, and a second tube. The fluid amplifier will be made of a type for positioning relative to the surface of the water in the swimming poll for developing a fluid pressure signal when an interface between liquid and gas at the water surface falls below a predetermined level. The fluid valve will be of a type responding to the fluid pressure signal developed by the fluid amplifier by opening in the presence of the signal and closing in the absence of the signal. The cap will be of a type which may be secured to a water circulation pipe at an inlet to the pool reservoir and it will have a restrictive orifice extending therethrough and also will include first and second taps extending therethrough. The first tube will be of a type for joining the fluid amplifier to the first tap in the cap for communication of the fluid amplifier with the circulating water in the pipe for developing the fluid pressure signal. The second tube will be of a type for joining the fluid amplifier to the fluid valve by passing through the second tap and the pipe for transmitting the fluid pressure signal to the fluid valve. With these features of construction, the fluid valve may be disposed within a supply line leading from an external water supply to the reservoir and the supply line may thereafter by automatically controlled by the fluid valve to maintain a predetermined water level within the pool reservoir.
The present invention is therefore directed to a liquid level control system for use with a swimming pool reservoir having an inlet and having an outlet located at a predetermined water maintenance level in the pool. It is further directed to such a liquid level control system in kit form for use with a previously installed swimming pool of the type described. Still other objects and advantages of the present invention will be appreciated from the details of construction and operation set forth in the accompanying specification, claims and drawings.